Persistent (a Haskell database library) does something like this, in a highly declarative way. You just declare your tables and their columns as Haskell data ty

Persistent (a Haskell database library) does something like this, in a highly declarative way. You just declare your tables and their columns as Haskell data types, and when it compiles your application it automatically migrates your database if it can do so non-destructively. If your change would destroy data or requires a default value for a new non-null column or something, it will give you an error message that tells you what you need to do. It's by far the best experience I've had working with a database in a programming language. Only problem is that it's Haskell specific, not portable to other languages.